Initial Dosimetric Experience With The Contura Multi-Lumen Radiation Balloon Applicator

Purpose/ObjectivesWe present our initial experience with the Contura Multi-lumen Radiation Balloon Applicator (SenoRx) with an emphasis on dosimetric comparison between the Contura and treatment using a single-lumen balloon.Materials/MethodsTo date, three patients have been treated with the Contura. Treatment planning was performed using the Plato Brachytherapy Planning System (Nucletron) which included an Inverse Planning with Simulated Annealing (IPSA) module. For comparison, an additional plan was generated using a single dwell position in the central lumen, simulating treatment with a single-lumen balloon. The treatment time for this comparison plan was chosen so as to produce the same prescription dose coverage (V100) of the planning target volume (PTV) as the clinically-used plan.ResultsIn the first patient, the balloon was implanted at a depth of 3 mm from the skin surface. The treatment plan employing a single, central dwell position yielded a maximum skin dose of 195% of the prescription dose, which exceeds the dose limit specified in the RTOG 0413 / NSABP B-39 protocol of 145%. In the Contura treatment plan for this patient, the maximum skin dose was 135%. In the second patient, the balloon was positioned close to the chest wall with surrounding air pockets comprising 8% of the PTV. The single-lumen treatment plan gave a maximum rib dose of 160% of the prescription dose. This was reduced to 130% in the Contura treatment plan. Target coverage was further improved by removing air around the applicator using the Contura's vacuum port and further shaping the dose distribution to accommodate remaining air pockets. In the third patient, the balloon was also positioned close to the chest wall. The single-lumen treatment plan gave a maximum rib dose of 207% of the prescription dose. This was reduced to 138% in the Contura treatment plan.ConclusionsThe multi-lumen design of the Contura offers added flexibility in treatment planning. A particular benefit is the ability to treat patients unable to meet dosimetric requirements if a single-lumen applicator were used. Purpose/ObjectivesWe present our initial experience with the Contura Multi-lumen Radiation Balloon Applicator (SenoRx) with an emphasis on dosimetric comparison between the Contura and treatment using a single-lumen balloon. We present our initial experience with the Contura Multi-lumen Radiation Balloon Applicator (SenoRx) with an emphasis on dosimetric comparison between the Contura and treatment using a single-lumen balloon. Materials/MethodsTo date, three patients have been treated with the Contura. Treatment planning was performed using the Plato Brachytherapy Planning System (Nucletron) which included an Inverse Planning with Simulated Annealing (IPSA) module. For comparison, an additional plan was generated using a single dwell position in the central lumen, simulating treatment with a single-lumen balloon. The treatment time for this comparison plan was chosen so as to produce the same prescription dose coverage (V100) of the planning target volume (PTV) as the clinically-used plan. To date, three patients have been treated with the Contura. Treatment planning was performed using the Plato Brachytherapy Planning System (Nucletron) which included an Inverse Planning with Simulated Annealing (IPSA) module. For comparison, an additional plan was generated using a single dwell position in the central lumen, simulating treatment with a single-lumen balloon. The treatment time for this comparison plan was chosen so as to produce the same prescription dose coverage (V100) of the planning target volume (PTV) as the clinically-used plan. ResultsIn the first patient, the balloon was implanted at a depth of 3 mm from the skin surface. The treatment plan employing a single, central dwell position yielded a maximum skin dose of 195% of the prescription dose, which exceeds the dose limit specified in the RTOG 0413 / NSABP B-39 protocol of 145%. In the Contura treatment plan for this patient, the maximum skin dose was 135%. In the second patient, the balloon was positioned close to the chest wall with surrounding air pockets comprising 8% of the PTV. The single-lumen treatment plan gave a maximum rib dose of 160% of the prescription dose. This was reduced to 130% in the Contura treatment plan. Target coverage was further improved by removing air around the applicator using the Contura's vacuum port and further shaping the dose distribution to accommodate remaining air pockets. In the third patient, the balloon was also positioned close to the chest wall. The single-lumen treatment plan gave a maximum rib dose of 207% of the prescription dose. This was reduced to 138% in the Contura treatment plan. In the first patient, the balloon was implanted at a depth of 3 mm from the skin surface. The treatment plan employing a single, central dwell position yielded a maximum skin dose of 195% of the prescription dose, which exceeds the dose limit specified in the RTOG 0413 / NSABP B-39 protocol of 145%. In the Contura treatment plan for this patient, the maximum skin dose was 135%. In the second patient, the balloon was positioned close to the chest wall with surrounding air pockets comprising 8% of the PTV. The single-lumen treatment plan gave a maximum rib dose of 160% of the prescription dose. This was reduced to 130% in the Contura treatment plan. Target coverage was further improved by removing air around the applicator using the Contura's vacuum port and further shaping the dose distribution to accommodate remaining air pockets. In the third patient, the balloon was also positioned close to the chest wall. The single-lumen treatment plan gave a maximum rib dose of 207% of the prescription dose. This was reduced to 138% in the Contura treatment plan. ConclusionsThe multi-lumen design of the Contura offers added flexibility in treatment planning. A particular benefit is the ability to treat patients unable to meet dosimetric requirements if a single-lumen applicator were used. The multi-lumen design of the Contura offers added flexibility in treatment planning. A particular benefit is the ability to treat patients unable to meet dosimetric requirements if a single-lumen applicator were used.